Asbestos is the term used for the fibrous forms of several naturally occurring minerals. Asbestos is a naturally occurring mineral that takes the form of hollow, microscopic fibers which are nearly indestructible. It can be densely packed into a tough, flexible and very useful material, which has been used for hundreds of years as an insulation, fireproofing, and building material.
The three main types of asbestos which have been commercially used are:
- Crocidolite (blue asbestos);
- Amosite (brown asbestos);
- Chrysotile (white asbestos).
Asbestos was, and still is commercially mined in Canada, South Africa and Russia. The other three types of asbestos are Tremolite, Actinolite and Anthophyllite.About 95% of all asbestos used in the U.S. has been chrysotile, the least toxic form of asbestos.
Where is asbestos found?
Asbestos is often a component in the following materials:
- Fireproofing
- Thermal insulation
- Boilers
- Building ventilation systems
- Ceiling tiles
- Vinyl floor tiles
- Dry wall, dry wall tape and plaster
- Texturized paints
- Roofing shingles, felt, tar, flashing
- Decorative building materials
- Sheathing on electronics and power cables
- Automotive brake pads and clutches
Why is it dangerous?
If you inhale asbestos fibres (which are long and thin) they can become lodged in the tissue of your chest and your body’s natural defences may not be able to easily break them down. This can lead to lung diseases (mainly cancers), particularly if you are repeatedly exposed to fibres over a number of years.
It is because fibres can remain in the lungs for so long that small, but repeated, exposures on different jobs over the years can lead to the development of an asbestos-related disease. This is why it is important to prevent or control exposure on every single job.All three main types are dangerous, but blue and brown asbestos are known to be more dangerous than white. The different types cannot usually be identified by their colour alone. The body naturally gets rid of any asbestos fibres taken in with food and water. Asbestos fibres cannot be absorbed through the skin.
What factors affect the risk of developing an asbestos-related disease?
Several factors can help to determine how asbestos exposure affects an individual.
- Dose (how much asbestos an individual was exposed to).
- Duration (how long an individual was exposed).
- Size, shape, and chemical makeup of asbestos fibers.
- Source of exposure.
- Individual risk factors, such as smoking and pre-existing lung disease.
Although all forms of asbestos are considered hazardous, different types of asbestos fibers may be associated with different health risks. For example, results of several studies suggest that amphibole forms of asbestos may be more harmful than chrysotile, particularly for mesothelioma risk, because they tend to stay in the lungs for a longer period of time . All common commercial types of asbestos have been associated with lung cancer .
When is asbestos a potential health hazard?
Asbestos that is "friable" may be crumbled, pulverized or reduced to powder in your hand when dry. Friable asbestos has the potential to release asbestos fibers that can become airborne, and potentially create a health hazard. Asbestos that is bonded, coated, painted, covered, or otherwise protected so that it doesn't release airborne fibers does not present a health hazard.
What can you do to limit your exposure to asbestos?
Most buildings, especially older ones, contain some amount of asbestos. But remember, asbestos is only a potential hazard if it is damaged and friable, releasing fibers into the air we breathe. If you come across something that appears to be friable asbestos, such as damaged insulation on a pipe, assume that it is asbestos, and notify your supervisor. Do not damage or disturb the area. A sample of the material will be taken and analyzed. If it is determined to be asbestos, it will either be removed or repaired so that it is protected and no longer releasing fibers.
If your job involves stripping or buffing floors that could be vinyl asbestos tile, this should be done infrequently, using a wet method. A soft, non-abrasive pad should be used, and the machine should be run at low speed (below 300 rpm). Do not burnish or dry-buff flooring unless it has sufficient finish so that the pad can't contact the bare floor.
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